JPH0386370A - Heat resistant structural body - Google Patents

Abstract

PURPOSE:To manufacture a heat resistant structural body usable under high temp. atmosphere by alternately joining corrugated sheets and flat sheets made of stainless steel through iron-based brazing filler metal to make honeycomb structure. CONSTITUTION:The stainless steel-made corrugated sheets 1 formed by continuously bending as wave shaped ruggedness and the stainless steel-made flat sheets 2 are alternately joined by using the iron-based brazing filler metal 3 to form the honeycomb structure which is flattened assembly of hollow column type cell 4. By this method, formation of the different kinds of compositions in base material, development of crack, corrosion of the base material, lowering of heat resistant temp., etc., are prevented, and the heat resistant structural body having excellent durability at high temp. is obtd. and advantageously used to catalyst converter for cleaning waste gas from a car engine.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a heat-resistant structure used in a high-temperature environment. That is, it relates to a heat-resistant structure in which corrugated sheets and flat sheets are alternately joined to form a honeycomb structure, and is used, for example, in a catalytic converter for purifying exhaust gas of an automobile engine, and to which a catalyst is attached as a support base. be.

``Prior art'' Such a heat-resistant structure consists of a stainless steel corrugated sheet material in which corrugated irregularities are continuously bent, and a flat stainless steel flat sheet material, which is made of an amorphous nickel-based brazing material. A honeycomb structure formed by alternately joining each other via a nickel-based brazing material, such as nickel-based brazing material, has been used in the past.

In other words, this kind of conventional heat-resistant structure uses corrugated sheet material as its base material in order to withstand use in high-temperature environments.

The plate material used was made of stainless steel, which has excellent corrosion resistance and heat resistance, and the brazing material used was a nickel-based brazing material, which also had excellent corrosion resistance and heat resistance. This heat-resistant structure is made of corrugated sheet materials and flat sheet materials that are alternately wound and bonded via a nickel-based brazing material to form a roll shape, or are laminated and bonded in multiple layers to form a laminated block shape. As a result, it forms a honeycomb structure and is used as a support for catalysts and for various other purposes.

"Problems to be Solved by the Invention" By the way, the following problems have been pointed out in such conventional heat-resistant structures.

Firstly, nickel-based brazing materials such as amorphous nickel-based filter materials are expensive, which poses a cost problem.

Second, the corrugated sheet material or flat sheet material, which is the base material made of stainless steel, and the nickel-based brazing material have significantly different compositions. Therefore, in brazing, when the nickel-based brazing filler metal diffuses into the base metal side due to joining, the interface between the base metals changes and tends to become a different composition, which has an adverse effect on use in high-temperature environments.

Thirdly, because the compositions of the base metal made of stainless steel, such as ferritic stainless steel, and the nickel-based brazing filler metal are significantly different, there is a difference in the coefficient of thermal expansion between the two, which results in a difference in the coefficient of thermal expansion between the two when used repeatedly. Cracks may occur.

Fourth, the nickel-based filler metal tends to corrode the stainless steel base metal, and even creates holes in the base metal, especially when the base metal is thin.

Fifth, since the melting point of the nickel-based brazing material is lower than that of the stainless steel base material, the heat resistance temperature of this heat-resistant structure depends on the remelting point temperature of the nickel-based brazing material, and is therefore set low. It becomes like this.

And these above-mentioned second. Third. 4th. Due to the fifth point, this conventional heat-resistant structure has a problem of poor durability at high temperatures.

Sixth, as an improvement measure to address these issues,
It has also been conventional practice to limit the amount of nickel-based brazing filler metal used, or to place it partially between the base metals instead of entirely. However, even with such improvement measures, the above-mentioned problems cannot be completely resolved, and it has been pointed out that the above-mentioned problems still occur.
Another problem was pointed out that it was troublesome to do the mapping.

Seventhly, such a conventional heat-resistant structure, for example,
When used in a catalytic converter for purifying the exhaust gas of an automobile engine, and when a catalyst is attached as a supporting matrix, problems have been pointed out in the catalyst purifying performance.

In other words, the presence of the nickel-based brazing filler metal makes it difficult for the washed coat of Algos, which is interposed between the base metal and the catalyst for surface treatment, to adhere to the base metal, which makes it difficult for the catalyst to adhere to the base metal. Problems also sometimes occurred. In particular, even if the catalyst adheres normally, the catalyst tends to dissolve into the nickel-based brazing material and become a solid solution, resulting in a low catalyst concentration on the surface of the base material. In this way, when a conventional heat-resistant structure is used as a supporting base for a catalyst, the presence of the nickel-based brazing material makes it difficult for the catalyst to adhere to it, and in particular, the catalyst tends to form a solid solution in the brazing material, resulting in poor catalyst purification performance. decreased, resulting in poor exhaust gas cleaning efficiency.

This point was pointed out in the conventional example.

In view of the above circumstances, the present invention has been made to solve the problems of the conventional methods described above.By using an iron-based brazing filler metal, the present invention is superior in terms of cost, and it is possible to use a different composition of the base material. This prevents various problems such as the occurrence of cracks, erosion of the base metal, and a decrease in heat resistance temperature, which results in excellent durability at high temperatures, and also facilitates the setting of iron-based brazing filler metals.
The purpose is to propose a heat-resistant structure.

"Means for Solving the Problem" The technical means of the present invention to achieve this object are as follows.

This heat-resistant structure has a honeycomb structure in which corrugated stainless steel sheets with continuous corrugated irregularities and flat stainless steel plates are alternately joined via iron-based brazing material. It becomes more.

"Function" Since the present invention consists of such means, it works as follows.

In this heat-resistant structure, an iron-based brazing material is used to join the corrugated plate material and the flat plate material. Therefore, the following 1st and 2nd points. Third
．． 4th. Fifth. 6th. It will be like number 7.

First, iron-based brazing materials are cheaper than nickel-based brazing materials such as amorphous nickel-based brazing materials.

Second, the iron-based brazing material and the corrugated plate material and flat plate material, which are stainless steel base materials, both have the same composition and are similar in terms of the iron base. Therefore, by brazing, even if the iron-based brazing filler metal diffuses into the stainless steel base metal, the interface between the base metals will not have a different composition.

Thirdly, the iron-based brazing filler metal and the stainless steel base metal have similar compositions. Therefore, the difference in the coefficient of thermal expansion between the two is small, and the occurrence of cracks between the two, which would otherwise occur if the difference in the coefficient of thermal expansion is large, can be avoided.

Fourth, iron-based brazing filler metals, unlike nickel-based brazing filler metals,
It does not attack the stainless steel base material.

Fifth, by sufficiently diffusing the iron-based brazing material into the stainless steel base material during brazing and joining, the remelting point temperature of the iron-based brazing material can be raised to the same level as that of the base material.

Sixth, in the case of iron-based brazing materials, a stable oxide film is formed on the surface of the brazing material after joining.

Seventhly, the iron-based brazing material is easily placed between the corrugated sheet material and the flat sheet material, which are the base materials, for example, as in the conventional general case, and is therefore easy to set.

"Example" The present invention will be described in detail below based on the example shown in the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing another embodiment.

First, its configuration etc. will be explained.

This heat-resistant structure is made by alternately joining corrugated stainless steel plates 1 with continuously bent corrugated irregularities and flat stainless steel plate plates 2 through iron-based brazing filler metals 3. It consists of a honeycomb structure.

To explain these in detail, first, as materials for the corrugated plate material 1 and the flat plate material 2, which are base materials, ferritic stainless steel, austenitic stainless steel, and other various stainless steels having excellent corrosion resistance and heat resistance are used. Then, such a stainless steel foil-like flat plate material is used as a flat plate material 2.
used as. The corrugated sheet material 1 is obtained by corrugating such a foil-like flat sheet material made of stainless steel using a corrugating machine, and is formed by continuously bending predetermined linear wave-like irregularities. Further, the iron-based brazing filler metal 3 is known to have iron as its main component and to have excellent corrosion resistance and heat resistance.
It is used in forms such as paste and amorphous.

And such stainless steel corrugated plate material 1 and flat plate material 2
and iron-based brazing filler metal 3.
The bottom of the laminated block-shaped heat-resistant structure shown in the figure is shaped.

First, the roll-shaped heat-resistant structure shown in FIG. 1 is made up of a corrugated sheet material 1 made of stainless steel and shaped like a belt, and a sheet of flat sheet material 2 made of stainless steel and shaped like a strip. To outline the manufacturing method, first, an iron-based brazing material 3 such as an amorphous iron-based brazing material is completely set between the corrugated sheet material 1 and the flat sheet material 2, and then the corrugated sheet material 1
and the flat plate material 2 are wound in multiple layers while being wound alternately from the center of the window. Alternatively, the setting of the iron-based brazing material 3 and the winding of the corrugated plate material 1 and the flat plate material 2 may be performed simultaneously. Thereafter, the iron-based brazing material 3 is melted by heating, and the corrugated plate material 1 and the flat plate material 2 are joined to produce a heat-resistant structure in a predetermined roll shape, such as a circle or an ellipse.

The heat-resistant structure in the form of a laminated block shown in Fig. 2 includes a plurality of corrugated plates 1 made of stainless steel and having a predetermined length, and a plurality of plate-like plates made of stainless steel and having the same predetermined length. A flat plate material 2 is used. To give an overview of the manufacturing method, first, such corrugated sheet material 1 and flat sheet material 2 are alternately stacked one on top of the other, with iron-based brazing material 3 being set and interposed on the entire surface, respectively. . Note that such interposition and intussusception may not be performed simultaneously but may be performed one after the other. After that, the iron-based brazing material 3 is melted by applying pressure and heating from above and below,
The corrugated sheet material 1 and the flat sheet material 2 are thus joined, and a heat-resistant structure in the form of a predetermined laminated block is manufactured.

The heat-resistant structure according to the present invention is not limited to the roll shape shown in FIG. 1 or the laminated block shape shown in FIG. 2, but may also be in the shape of a lot number.

In this heat-resistant structure, each space of the corrugated sheet material 1 is connected to the flat sheet material 2.
The corrugated sheet material 1 is divided into independent spaces by
and the flat plate material 2 constitute cell walls, forming a honeycomb structure which is a planar assembly of hollow columnar cells 4. Generally, such a honeycomb-structured heat-resistant structure has strong hot strength, light weight, high rigidity and strength, excellent fluid rectification effect, easy bottom shape, and excellent cost. These characteristics are known. Therefore, the heat-resistant structure concerned, for example,
The corrugated sheet material 1 and the flat sheet material 20 are used as supporting bodies for catalytic converters for purifying exhaust gas of automobile engines.
A catalyst such as platinum or palladium is attached to the surface.

The above is the explanation of the configuration, etc.

The operation etc. will be explained below.

In this heat-resistant structure, an iron-based brazing material 3 is used to join the corrugated sheet material 1 and the flat sheet material 2. Such a heat-resistant structure is used in a high-temperature environment, for example, as a support for a catalyst or the like. So here's the first one. Second. Third. 4th. Fifth. 6th. 7th. It will be like the 8th one.

First, the iron-based brazing filler metal 3 is cheaper than nickel-based brazing filler metals such as amorphous nickel-base brazing filler metals conventionally used in this type of heat-resistant structure.

Second, an iron-based brazing filler metal 3 and a corrugated sheet material 1 made of stainless steel as a base material. The composition is similar to the flat plate material 2 in that they both have an iron base. Therefore, brazing is performed by joining the iron-based brazing material 3 to the stainless steel corrugated plate material 1. Even if it diffuses to the flat plate material 2 side, the interface between the corrugated sheet material 1° and the flat plate material 2 will not have a different composition. In other words, as in the case where a nickel-based brazing filler metal is conventionally used in this type of heat-resistant structure, the corrugated sheet material 1. There is no possibility that the interface, which is the joint surface of the flat plate material 2, changes and becomes a different composition.

Thirdly, in this way, iron-based brazing filler metal 3 and stainless steel M! ! !
! For example, a corrugated sheet material that is a base material made of ferritic stainless steel 1. The composition is similar to that of the flat plate material 2. Therefore, the difference in coefficient of thermal expansion between the two is small, and cracks between the two can be avoided, which would otherwise occur when the difference in coefficient of thermal expansion was large, as was the case when nickel-based brazing filler metal was used in this type of heat-resistant structure. Ru.

Fourthly, the iron-based brazing filler metal 3 is different from the nickel-based brazing filler metal conventionally used in this type of heat-resistant structure, and the corrugated plate material 1 which is the base material made of stainless steel. It does not erode the flat plate material 2.

Fifth, the iron-based brazing material 3 can be heated to its remelting point temperature by sufficiently diffusing the corrugated sheet material 2, which is the base material made of stainless steel, over time during brazing, that is, heating. Corrugated sheet material 1. It can be pulled up to the same level as the flat plate material 2. In other words, unlike when a nickel-based brazing filler metal is conventionally used in this type of heat-resistant structure, the heat-resistant temperature of the heat-resistant structure is not set depending on its low remelting point temperature.

Sixthly, in the case of the iron-based brazing material 3, unlike the nickel-based brazing material conventionally used in this type of heat-resistant structure, a stable oxide film is formed on the surface of the brazing material after joining.

Seventhly, the setting of the iron-based brazing filler metal 3 is easy, as it is disposed entirely between the corrugated plate material 1 and the flat plate material 2, which are the base materials, for example, as in the conventional general example. In other words, there is no regulation to limit the amount of nickel-based brazing filler metal used or to place it only partially, as in the conventional improvement measures mentioned above. Easy to set up.

Eighth, when this heat-resistant structure is used, for example, in a catalytic converter for purifying the exhaust gas of an automobile engine, and a catalyst is attached to the surfaces of the corrugated sheet material 1 and the flat sheet material 2 as supporting bodies. becomes as follows. That is, in this case, unlike the nickel-based brazing material conventionally used in this type of heat-resistant structure, the iron-based brazing material 3 is interposed between the corrugated sheet material 1 and the flat material 2, which are the base materials, and the catalyst for surface treatment. There is no problem with the adhesion of the alumina washcoat. Further, in particular, the catalyst does not penetrate into the iron-based brazing material 3 to form a solid solution, and the catalyst concentration on the surface does not decrease.

As described above, when this heat-resistant structure is used as a support for a catalyst, the catalyst purification performance is improved and the exhaust gas purification efficiency is excellent.

The above is the explanation of the operation, etc.

"Effects of the Invention" As explained above, the heat-resistant structure according to the present invention exhibits the following effects by using an iron-based brazing material.

First, the iron-based brazing filler metal is relatively inexpensive, making this heat-resistant structure cost-effective.

Second, even if the iron-based brazing filler metal diffuses into the corrugated plate material and flat plate material, which are the stainless steel base materials, due to brazing, the compositions of the two are similar, so the interface between the base materials will have a different composition. There's nothing to do. From this point of view, there is no adverse effect on the use of the heat-resistant structure in a high-temperature environment.

Thirdly, since the iron-based brazing material and the stainless steel base metal have similar compositions, the difference in their thermal expansion coefficients is small. Therefore, even if this heat-resistant structure is used repeatedly, cracks will not form between the iron-based brazing material and the base material.

Fourth, iron-based brazing filler metals do not corrode stainless steel base metals. Therefore, in this heat-resistant structure, even if the base material is particularly thin, holes will not be formed in the base material due to erosion.

Fifth, by sufficiently diffusing the iron-based brazing material into the stainless steel base material during brazing and joining, the remelting point temperature of the iron-based brazing material can be raised to the same level as that of the base material. Therefore, the temperature limit of this heat-resistant structure is not set particularly low by the brazing material.

Sixth, in the case of iron-based brazing materials, a stable oxide film is formed on the surface of the brazing material after joining. As a result, this heat-resistant structure is prevented from progressing to oxidation after the fact.

These above-mentioned second. Third. 4th. Fifth. Due to the sixth point, this heat-resistant structure is suitable for use in high-temperature environments and has particularly excellent durability at high temperatures.

Furthermore, seventhly, the setting of the iron-based brazing material is easy, and this heat-resistant structure is easily manufactured.

In this way, the problems that existed in this type of conventional example are completely eliminated, and the effects of the present invention are remarkable and great.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a heat-resistant structure according to the present invention. FIG. 2 is a perspective view showing another embodiment. 1... 2... 3... 4... Corrugated plate material Flat plate material Iron-based filler metal Cell diagram Diagram

Claims (1)

[Scope of Claims] A honeycomb structure in which corrugated stainless steel plates in which corrugated irregularities are continuously bent and flat stainless steel plates are alternately joined via an iron-based brazing material. A heat-resistant structure characterized by: